The use of impingement heating and cooling devices in apparatus for thermally treating food products has previously been disclosed. Such devices employ columnated jets of a temperature-controlled gas which impinge against the surface of a food product moving relative thereto. These devices are disclosed, for example, in U.S. Pat. Nos. 3,884,213; 4,154,861; and 4,289,792. In addition to the foregoing patents that have already issued to the present inventor, such apparatus is further disclosed in copending application Ser. No. 286,060, filed July 22, 1981.
More recently, an improved apparatus and method for rapidly heating and/or cooling food products and for substantially equilibrating the temperature throughout such food products was disclosed in application Ser. No. 06/341,640, filed Jan. 22, 1982. Notwithstanding the considerable advantages of the apparatus and methods previously disclosed, however, there remains a need for a compact and efficient apparatus that is able to deliver a temperature-controlled gas to at least one surface of a food product at different thermal energy transfer rates within a single cabinet or enclosure.